I–3 Effect of Low-Intensity Pulsed Ultrasound (LIPUS) in Rats With Healing Socket

Abstract

Objective: Low-intensity pulsed ultrasound (LIPUS) has been widely used as a potent therapeutic tool to accelerate fracture healing. In the oral environment, however, the effect of LIPUS on wound fracture healing after implant placement and dental operation has not been well explored. This study aimed to characterize the local as well as humoral effect of LIPUS treatment of tooth extraction sockets in aged rats. Methods: Right maxillary first molars were removed from retired female breeder rats in control and LIPUS groups. LIPUS was applied extrabuccally to the socket for 20 minutes every 24 hours for 2 weeks starting 1 day after the extraction. The blood flow rate was measured by laser-Doppler flowmetry at the extraction socket, the dorsum of the tail base, and the dorsum of foot prior to and 2 hours after the 20-minute LIPUS treatment on 3, 7, 11 and 14 days after the tooth extraction. Results and Discussion: On and after post-extraction day 7, the baseline flow rate in the socket of the LIPUS group rats was significantly higher than that of the control group. Increased peripheral blood vessels are confirmed with histochemical staining of the undecalcified sections prepared from the experimental and control sockets. The flow rate in the socket of the LIPUS group rats transiently dropped after the exposure and returned to the basal level in about 2 hours. LIPUS exposure also affected the blood flow rate transiently but positively at remote sites such as foot. Angiogenic effect, which may involve systemic propagation of reactive molecule(s), was suggested.